As you navigate your path to parenthood, understanding the success rates of embryos based on their developmental stage can help you feel confident as you embark on this life-changing journey. From day two to day seven, we’re here to walk you through each stage of the embryo transfer process.
If you have embryos created or are looking to connect with a fertility clinic in your area, contact us online now to connect with a specialist.
Day 2 Embryo Transfer Success Rates
Day two embryos, also known as cleavage-stage embryos, are typically around 2-4 cells at this stage. While not as commonly transferred as day three or day five embryos, some clinics may still perform day two transfers under specific circumstances.
The day 2 embryo transfer success rates are generally lower compared to transfers at later stages. According to research, the implantation and live birth rates for day two embryos are comparable to day three embryo transfers with an implantation rate of 23.8%. Day three embryo transfer rates tend to be less favorable due to the limited development time and lower assessment accuracy of embryo viability.
Day 2 transfers may be considered in cases where there are concerns about the embryo's ability to survive in culture conditions for longer periods.
Day 3 Embryo Transfer Success Rates
Day three embryos are also known as cleavage-stage embryos. At this point, the embryo typically has around 6-8 cells.
According to a study published by the National Center for Biotechnology Information (NCBI), the day 3 embryo transfer success rates vary. If 32% of women undergoing a cycle have a successful outcome, the live birth rate per woman can be anywhere from 28% to 39%.
Day three transfers were historically more common but have decreased due to higher success rates associated with advanced development.
Day 4 Embryo Transfer Success Rates
Day four embryos are also known as morula-stage embryos. Comparing day four to day five embryos, a study indicated that the day 4 embryo transfer success rates are generally lower than those of day five blastocysts. This stage is less commonly used for transfers as day five embryos tend to have better implantation and live birth rates.
Day 5 Embryo Transfer Success Rates
Day 5 embryos are known as blastocysts. At this stage, the embryo has developed a fluid-filled cavity and begun differentiation into the cells, forming the placenta and fetus.
The 5 day frozen embryo transfer success rates are significantly higher compared to earlier stages. A comprehensive study highlighted that for patients aged 35-37 years, implantation rates were notably higher for day five transfers compared to day six. Day five embryos have undergone more development, allowing for better selection of the most viable embryos, which can lead to higher pregnancy and live birth rates.
Day 6 Embryo Transfer Success Rates
Day six embryos are also blastocysts but have had an extra day in culture compared to day five embryos. While day 6 embryo success rates are decent, they’re generally lower than those for day five embryos. For example, the live birth rates for day six transfers are promising but less favorable than day five, with a noted live birth rate of approximately 21.28%.
Day six embryos can still be viable, especially if day five embryos are not ready for transfer. The additional day in culture can sometimes improve the chances of selecting an optimal embryo, though the slight reduction in success rates must also be considered.
Day 7 Embryo Transfer Success Rates
Day seven embryos are extended blastocysts that had an additional day in culture beyond the typical day five and day six stages. This extended culture period is less common but can be utilized in specific cases.
The day 7 success rates are typically lower than day five and day six transfers. While some day seven embryos can result in successful pregnancies, their overall implantation and live birth rates are typically lower. For example, one study showed that day seven embryos, although viable, have a 36% live birth rate, compared to 68.5% for day five and 55.2% for day six embryos.
No matter where you are in your journey to parenthood, we’ll always be here to help you get one step closer to holding your baby in your arms. To begin preparing for your surrogate’s embryo transfer, contact us online now to connect with a specialist.